Lüttke Thomas, Kunze Christian, Flesch Klaus, Dilling Jörg, Fohlmeister Jens, Hummrich Holger, Arndt Robert, Krzikalla Annegret, Lucks Christian, Kuhn Thomas, Vink Annemiek, Rühlemann Carsten
Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655, Hannover, Germany.
IAF-Radioökologie GmbH, Wilhelm-Rönsch-Straße 9, 01454, Radeberg, Germany.
Sci Rep. 2025 Sep 4;15(1):32303. doi: 10.1038/s41598-025-10842-0.
The strategic importance of metals found in deep-sea polymetallic nodules has spurred a surge in interest for their exploitation. However, nodules are known to incorporate radionuclides during their growth, so that any industrial processing would involve classifying them as naturally occurring radioactive materials (NORM). As the start of deep-sea mining gets closer, concerns about elevated exposure to radiation that could result from the handling of nodules has recently been raised. In this study, we address this issue within the framework of radiation protection regulations. For the first time, we present estimates of effective doses associated with laboratory work and industrial-scale exploitation, transportation and metallurgical processing of polymetallic nodules. Estimates are based on an analysis of all long-lived radionuclides from the three natural decay chains of uranium-238, uranium-235 and thorium-232 and on radon exhalation rates from dry nodules. We show that effective doses for laboratory workplaces are well below the threshold of 1 millisievert per calendar year (mSv/a) for occupational exposure, even under the most conservative assumptions. Furthermore, we find that the effective doses for personnel on nodule transport vessels and metallurgical processing facilities may exceed the threshold in a conservative scenario. However, with standard radiation protection and mitigation measures common in other NORM-affected industries, effective doses can be kept well below the occupational exposure limit.
深海多金属结核中发现的金属具有重要的战略意义，这激发了人们对其开采的浓厚兴趣。然而，已知结核在生长过程中会吸收放射性核素，因此任何工业加工都将涉及将它们归类为天然放射性物质（NORM）。随着深海采矿的临近，最近人们对处理结核可能导致的辐射暴露增加表示担忧。在本研究中，我们在辐射防护法规的框架内解决了这个问题。我们首次给出了与多金属结核的实验室工作、工业规模开采、运输和冶金加工相关的有效剂量估计值。这些估计值基于对铀 - 238、铀 - 235和钍 - 232这三个天然衰变链中所有长寿命放射性核素的分析以及干结核的氡析出率。我们表明，即使在最保守的假设下，实验室工作场所的有效剂量也远低于职业暴露每年1毫希沃特（mSv/a）的阈值。此外，我们发现，在保守情况下，结核运输船上和冶金加工设施中的人员的有效剂量可能会超过阈值。然而，通过其他受NORM影响行业常见的标准辐射防护和缓解措施，可以将有效剂量保持在职业暴露限值以下。
